A very disinfected stethoscope

A couple of years ago I bought a Littmann 3200 electronic stethoscope. Love the thing. Fantastic (and adjustable) sound and recording capability and Bluetooth connection to upload those sounds to a companion app.

A couple of weeks back, the stethoscope started to glitch. Every now and then it would hard reset when I pressed the “-” button so I thought that was the end of it. I ordered a new one, planning on disassembling the old one once I had another good one. Today was that day.

Anyhow, as soon as I removed the membrane, it was pretty obvious what the problem was. Under the membrane, around the microphone, there was quite a collection of clear and sticky fluid. Looks a lot like the alcohol we use to disinfect hands and surfaces. I’m pretty sure the cleaning crew also cleans any stethoscopes they encounter and don’t think twice about dunking even electronic ones. I can’t imagine any other reason for fluid in my stethoscope.

Surprisingly, these stethoscopes are fairly easy to take apart, at least if you start at the right end, under the membrane. Sadly, the one part that can’t be removed is the keypad. So I never got to clean that out. But just by disassembling the scope and putting it back together, I seem to have fixed the problem.1

In the pictures, the blue one is the old, flaky one. The red (“burgundy”) is the new one. There’s a four year difference between them, but they have the exact same version of firmware.

Now I’ve got two… the blue one is the old one, the red… um… burgundy one is the new one.
Back side of microphone. Board, chip side.
Front of microphone and back of board. You can see some of the sticky fluid still on the microphone frame, though I did wipe most of it off before taking the picture.
After disconnecting the microphone and board.
Display part.
Empty shell. Almost. The keypad and its connector ribbon can’t be removed without major destruction.
The battery holder is pushed out the other way.
The LCD display module.
  1. I won’t leave it on my desk overnight anymore.

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